It has been found that the prior art power steering mechanisms on the market have the following drawbacks:
1. they are high in cost; PA0 2. they are difficult to maintain; PA0 3. they are too sensitive; PA0 4. the original steering mechanism will be inoperative when the power steering mechanism does not work.
Therefore, it is an object of the present invention to provide an auxiliary power steering mechanism which may obviate and mitigate the above-mentioned drawbacks.